Shoe for deep-water-running exercise

ABSTRACT

An apparatus for use in exercising in water, preferably deep water running, includes a shoe that is configured to be worn by the user. The shoe includes a plurality of drag-generating elements attached to and extending from each side of said shoe for generating drag forces on the shoe during movement in water. The drag-generating elements generate more drag for movement of said shoe in a rearward direction than in a forward direction and are sized and positioned to simulate the forces on the user&#39;s foot arising from land-based running.

This application is a Continuation of U.S. patent application Ser. No.10/545,788, filed Aug. 17, 2005, which is the national stage ofInternational Application Number PCT/US2004/043954, filed Dec. 29, 2004,which was published in English, and claims priority of U.S. ProvisionalApplication No. 60/533,049 filed Dec. 30, 2003.

TECHNICAL FIELD

This invention relates to an apparatus for wearing on a user's footduring the exercise known as deep water running (DWR) to simulaterunning on land.

BACKGROUND ART

Approximately 30 million Americans participate in running as a form ofgeneral exercise for fitness and health. It has also been estimated thatup to 70% of this population will incur a running-related injury.Running has been described as “essentially a series of collisions withthe ground,” and these collisions typically exhibit vertical groundreaction forces (VGRF) of 1.5 to 3 times the runner's body weight. Theseimpact forces, as well as training errors resulting from increasing thetotal volume of mileage too rapidly and/or excessive mileage, are atleast partially responsible for the creation of many running-relatedinjuries.

A known method of decreasing the running impact forces and the negativeeffects of excessive mileage is to supplement a runner's trainingprogram with deep-water running (DWR) in a pool. This mode of trainingallows the runner to mimic the terrestrial running style in the poolwhile typically using a buoyancy device, e.g., AquaJogger®, to supportthe runner's weight. It has been reported that the DWR training methoddecreases spinal and joint compressive loading, which decreases thelikelihood of incurring running-related injuries. A rationale fordeep-water running (DWR) is that it allows the runner to train withmovements similar to that found on land without incurring the impactforces, which greatly reduces the repetitive loading of themusculoskeletal system. Rehabilitation after injury, rather thanprevention, is the most common use of deep water running.

Despite the increasing use of DWR for rehabilitation and more recentlyas training to supplement a normal regimen, very little research focuseson the DWR technique. Several sources describe “proper” DWR techniques,but it appears that the most common DWR style is characterized by ahigh-knee or piston-like leg action. In contrast, the cross-countrystyle is intended to be more like land-based running. Thespecificity-of-training principle suggests that the movement pattern ofDWR should be closely aligned with that of terrestrial running tomaximize the benefit to the runner. The cross-country style of DWR isthe one most like terrestrial running, particularly in terms of thehorizontal ankle displacement.

SUMMARY OF THE INVENTION

In accordance with the invention, a shoe is particularly designed foruse in DWR exercise to enhance the effects of the accommodatingresistance provided by the water when the foot is moving from theanterior (front) to the posterior (back) portion of the gait. The uniqueconstruction of the shoe in accordance with the invention allows therunner to maintain proper running technique throughout the normal rangeof motion and to benefit from enhanced resistance in the appropriateplanes of motion and minimal drag when appropriate. As used herein,“shoe” means any article that is attached to a user's foot and includesthat commonly known as a sandal, or a sock, or other similar articles.

The shoe according to the invention utilizes the accommodatingresistance properties of water by increasing or decreasing drag tomaximize resistance in the appropriate planes of motion inherent in arunning gait. Increased overall benefit to the runner and an improved“feel” of the DWR exercise are achieved. Applicants' research alsosuggests that wearing a shoe during DWR enhances kinesthetic perceptionand further helps the runner achieve a gait during DWR that is moresimilar to that of land-based running.

In the preferred embodiment, enhanced resistance is achieved byattaching three small scoops to each side of the shoe at the forefoot,mid-foot, and heel areas of the shoe. The scoops create fluid drag, andthe size, configuration, and placement of the scoops are important tothe effective operation of the shoe in DWR.

The scoops must be configured and placed such that they conform both tothe characteristics of the shoe and to the user's foot. For example, thescoops are generally placed on the sides of the shoe, and the front partof the side of a shoe generally tapers downward such that the sides areshorter in that part of the shoe. Accordingly, the height of the scoopin the forward part of the shoe is often limited. In addition,applicants have found that the characteristics of the user's foot affectthe size and placement of the scoops and the materials from which thescoops may be made. In particular, the foot articulates at the ankle andthe ball, which means that rigid scoops that will restrict that motionmust be avoided.

Applicants have further discovered that the size and placement of thescoops affect the stability of the shoe during the running motion.Instability of the shoe, in turn, is transmitted to the runner and has asignificant impact on its feel and its ability to simulate running onland. In addition, instability of the shoe results in transmission offorces to the runner, which could affect the runner's hip, knee, andankle joints.

In accordance with the invention, a DWR shoe has more than one scoopattached to each side of the shoe such that they are generallysymmetrical with respect to a vertical plane passing through thelongitudinal axis of the shoe. One objective in placing the scoops in asymmetrical fashion is to ensure that the forces arising from fluid dragon both sides of the shoe are approximately equal. This approachgenerally is more effective in simulating land running. While the mainpurpose of the invention is the simulation of land or treadmill running,it is within the contemplation of the invention to arrange the scoops inan asymmetrical fashion, for example, for rehabilitation.

Applicants have found that placing a single scoop, or fin, on the shoeor a single scoop on each respective side of the shoe generates flutterin the shoe as it moves through the water. This flutter is substantiallyeliminated by the use of more than one scoop longitudinally arranged onthe side of the shoe. Further, a shoe with a single scoop could lead tohyperextension of the runner's knee.

The use of several scoops spaced along the side of the shoe distributesthe drag forces along the foot longitudinally, which reduces flutter inthe yaw direction (i.e., about a vertical axis). One reason for this maybe that the angle of the foot changes during the running motion, withthe foot pointing more upward (dorsiflexed) during the forward part ofthe motion. It must also be remembered that the scoops create torque onthe shoe, and very large scoops are therefore not generally desired forthat reason.

The fins may be configured to create different amounts of drag, andapplicants have found it generally advantageous for the scoop locatednearest the back of the shoe to create the largest amount of drag. Theuse of the largest scoop at the rear of the shoe is advantageous becausethe rear part of the shoe is better able to accommodate a large scoopand also because that places the most drag at the runner's heel, whichfurther assists in simulating the feel of land-based running.

The shape and size of a scoop are primary factors affecting the drag itproduces during the forward and aft movements. Because the foot does notmove strictly linearly (see FIG. 1) the shape affects the drag appliedto the shoe in a variety of directions. It will also be appreciated thatthe movement of a runner's foot is rather complex because in normalrunning the foot rotates as the toes come up during the forward motionand then rotates down during the rearward motion. In the preferredembodiment the scoops are generally conical with the front surfaces ofthe scoops sloping toward the side of the shoe from the back to thefront. This configuration reduces drag in the forward direction whileproviding desired drag in the aft direction.

Preferably the scoops in the front of the shoe are smaller than those atthe rear. This assists in reducing flutter it is believed by reducingthe effects of twisting (torsion) forces on the front of the foot byscoops that are too wide.

Configuring the scoops with tapered front surfaces also allows the waterto flow around the rear scoop and engage the scoop in front of it withless turbulence. Further, this reduces the shadowing of a forward scoopby a rearward one. Thus, the majority of the drag is provided by therearmost scoop, and the drag provided by the foremost scoop is theleast.

In the preferred embodiment, the scoops are located on the shoe in alower position of the sidewall. This places the drag forces lower on theshoe to further assist in simulating the application of forces thatarise during land running.

An object of this invention is to provide a shoe that simulatesland-based running.

Another object of this invention is to provide a shoe for use in DWRexercising.

A further object of this invention is to provide a shoe having severalelements that create fluid arranged on a shoe for creating dragsimulating land-based running.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plot showing the typical motion of a foot during dry-landrunning on a treadmill.

FIG. 2 is a plot showing typical motion of a foot during deep waterrunning with the article of the invention.

FIG. 3 is a bottom perspective view of a DWR shoe according to theinvention.

FIG. 4 is a top perspective view of the shoe shown in FIG. 3.

FIGS. 4 a, 4 b, and 4 c illustrate preferred configurations andarrangements of the scoops.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is a shoe, as defined above, for use in deep waterrunning (DWR). FIG. 1 illustrates the motion of the ankle of a runnerwhen running on a treadmill. The curve 2 illustrates motion in avertical plane when the runner is viewed from the right side, and thetreadmill is moving from right to left. It will be appreciated that thebottom, somewhat linear portion, 4 of the graph represents movement ofthe foot when in contact with the treadmill.

FIG. 2 illustrates motion of the ankle of a runner wearing a shoeaccording to the invention. It will be appreciated that the curve 6approximates the motion shown in FIG. 1. The portion 8 of the graph 6represents that part of the motion of the foot during which increasedresistance is provided by the shoe of the invention.

When worn by the user while running in deep water to simulate land-basedrunning, the shoe provides low-impact water exercise. The foundation ofthe shoe preferably resembles a standard running shoe. The materials areselected for use in water, such as materials that are less susceptibleto chemical attack from chlorine. The shoe may have a fabric upper andan elastomeric sole and may also be provided with one or more openingsor the like to allow water to drain out of the shoe after use. Attachedto the foundation along each side of the shoe are scoop-shapedprotrusions. These protrusions are shaped to minimize hydrodynamic dragon the foot as it moves forward through the water. This shape alsomaximizes the drag as the runner moves his foot back though the water.Optimally the drag when moving in the backwards direction is 25%-30%greater than when moving in the forward direction.

The scoop shape, size, material and position on the foundation areimportant to the performance of the device. The preferred embodiment ofthe invention uses three scoops per side, lined up in a row from the toeof the foundation to the heel. The scoop located nearest the heel is thelargest of the three. The center scoop, located near the arch, issomewhat smaller. The scoop nearest the toe is the smallest. The scoopmaterial is a semi-rigid plastic, which can be formed to the desiredshape and affixed to the side of the foundation.

FIGS. 3 and 4 are perspective views of a shoe 2 according to theinvention. A shoe foundation 10 may be formed in any of several shapes,a typical running shoe being illustrated. As noted above, however, thefoundation may be in the form of a sock, a sandal, a boot, or the like.Preferably, however, the foundation is relatively small and light toprovide the feel of a running shoe to simulate land running. The shoeaccording to the invention includes a plurality of scoops 12 attached tothe sides of the shoe for the purpose of providing drag during therearward movement of the shoe.

FIGS. 4 a, 4 b, and 4 c illustrate preferred scoops for use with a shoeof the invention. FIG. 4 a is a perspective view of three scoops 14, 16,and 18, which are preferably arranged in a line as shown on a shoe.Scoop 14 would be placed at the rear of the shoe and is the largest ofthe three scoops. Scoop 14 is preferably placed at the rear of the shoeand may be placed at the heel so that the rearmost part of the scoop 14is flush with the rear of the shoe. This configuration allows the scoopto engage the water without the effects of turbulence created by thewater flowing around the shoe before engaging the scoop. Thus, thisscoop can be configured to provide the largest degree of drag. Scoop 16is smaller than scoop 14 and scoop 18 is smaller than scoop 16.

It will be appreciated that in the preferred embodiment, the scoops areattached to the sides of the shoe. This applies the drag forces to theside of the user's foot near the bottom of the shoe to simulate theforces applied by contact with the ground in land-based running. Thus,the scoops are preferably placed on the side of the shoe well below theankle, and in some instances may actually extend onto the bottom (sole)of the shoe.

FIG. 4 b is a side view of the scoops shown in FIG. 4 a and FIG. 4 c isan end view. These figures show some of the relevant dimensions of thescoops. Dimension “A” of FIG. 4 c is the depth of a scoop, “B” is theheight of a scoop, and “C” is the length of a scoop and “D” is thespacing between adjacent scoops.

In the preferred embodiment, a shoe has 2 to 4 scoops arrangedlongitudinally on each side of a shoe, and preferably has three suchscoops on each side. It is within the contemplation of the invention toprovide a different number of scoops on each respective side, but in thepreferred embodiment the scoops are symmetrical about a vertical plane.The depth of the scoops (“A”) may be in the range of from about 6 mm toabout 40 mm and more preferably in the range of from about 9 mm to about22 mm. The height of the scoops (“B”) may be in the range of from about19 mm to about 75 mm and more preferably from about 25 mm to about 63mm. The lengths of the scoops (“C”) may be in the range of from about 12mm to about 50 mm and more preferably from about 18 mm to about 45 mm.The spacing of the scoops may be in the range of from about 50 mm toabout 75 mm and preferably about 57 mm.

In a preferred embodiment, five scoops of generally arcuate crosssection, tapered configuration are configured as set forth in thefollowing table, and the three largest scoops are used for larger shoes(e.g., sizes 13, 14), the three smallest scoops are used for smallershoes, and intermediate scoops are used with shoes of intermediate size.The difference in drag between a scoop and the adjacent scoop may be inthe range of 10% to 20%.

TABLE A SCOOP 1 2 3 4 5 “A” 22.1 mm 18.1 mm 14.6 mm 11.5 mm  8.9 mm “B”62.7 mm 51.5 mm 41.3 mm 32.9 mm 25.2 mm “C” 44.4 mm 36.4 mm 29.2 mm 23.3mm 17.9 mm

Applicants have found that a typical running shoe without scoopsprovides about eleven percent more drag during rearward motion than inforward motion, when the average velocity of the foot is about 3.6ft./sec. In the preferred embodiment with the scoops of Table A attachedto the sides of the shoe, the scoops produce 12% to 33% more drag in therearward direction when the average velocity of about 3.6 ft./sec. Inthe preferred embodiment, the scoops provide about 28% increased dragduring rearward movement.

It will be appreciated that while the preferred embodiment utilizesscoops to provide the desired degree of increased drag as describedabove, other elements may be provided with similar effect. It is notnecessary to use a hollow “scoop” as such, and it may be possible to useother drag—creating elements, such as a flat or slightly curved paddle,or the like, that extends outward from the sides of the shoe. The frontof such an element may include a fairing or similar structure to reducethe drag during forward motion of the foot. An advantage of a scoop isthat it is conveniently attached to the shoe by stitching and may beconformed to the shape of other structures on the shoe whereby the samestitching is used for the scoop as well as for the other structures.

Modifications within the scope of the appended claims will be apparentto those of skill in the art.

1. Apparatus for use in exercising in water comprising a shoe foundation(10) configured to be attached to the foot of a user, the said shoefoundation (10) being configured to extend along the said foot when wornby the said user and comprising forefoot, mid-foot, and heel areas, aplurality of drag-generating elements (12) attached to each side of thesaid shoe foundation (10) and spaced along the said shoe foundation (10)from the forefoot area to the heel area and below the user's ankle whenthe said shoe foundation (10) is worn by the said user, said draggenerating elements generating drag forces in water on the said footduring use, wherein the said drag-generating elements (12) generatelarger drag forces in water when the said shoe foundation (10) is movedrearward at a given velocity than when moved forward at the saidvelocity and generate substantially equal drag forces on both sides ofthe said shoe foundation (10).
 2. Apparatus according to claim 1 whereinsaid drag-generating elements on each side of said shoe are spaced fromeach other in the direction of the longitudinal axis of said shoe. 3.Apparatus according to claim 2 wherein said drag-generating elementsprovide increased drag for rearward motion in water of at least 12%. 4.Apparatus according to claim 2 wherein there are three of saiddrag-generating elements on each side of said shoe.
 5. Apparatusaccording to claim 1 wherein a respective rearmost one of saiddrag-generating elements is located at the rear of each side of saidshoe.
 6. Apparatus according to claim 5 wherein said rearmost one ofsaid drag-generating elements is larger than the other drag-generatingelements on the same side of said shoe.
 7. Apparatus according to claim6 comprising three drag-generating elements on each respective side ofsaid shoe.
 8. Apparatus according to claim 7 wherein a foremostdrag-generating element on each respective side of said shoe is smallerthan the other drag-generating elements on the same side of said shoe.9. Apparatus according to claim 1 wherein each of said drag-generatingelements comprises a scoop having an open end and a tapered frontsurface.
 10. Apparatus according to claim 9 wherein the depth of saidscoop is from about 6 mm to about 40 mm, the height of said scoop isfrom about 19 mm to about 75 mm, and the length of said scoop is fromabout 12 to about 50 mm.
 11. Apparatus according to claim 10 wherein thedepth of said scoop is from about 9 mm to about 22 mm, the height ofsaid scoop is from about 25 mm to about 63 mm, and the length of saidscoop is from about 18 mm to about 45 mm.